Emerging data suggest that a significant proportion of racial and ethnic asthma disparities may be attributable to non-biologic factors. Importantly, racial and ethnic asthma disparities are explained to a significant extent by socioeconomic disparities. Because of longstanding housing discrimination, racial and ethnic minorities are concentrated in poor neighborhoods, and asthma-associated indoor and outdoor exposures likely vary by neighborhood poverty. These exposure differences could lead to phenotypic differences in asthma among residents of high- vs low-poverty neighborhoods. We therefore hypothesize that both environmental exposures and asthma phenotypes covary with neighborhood poverty, and that differences in exposure profiles between high- and low-poverty neighborhoods explain, at least in part, differences in asthma phenotypes. To test this hypothesis, we will (1) examine changes in environmental exposures and asthma phenotypes among an established prospective cohort study of low-income, Black children with asthma who move from high- to low-poverty neighborhoods in the Baltimore metropolitan area (Mobility Asthma Project (MAP)); and (2) conduct a cross-sectional study of 300 ethnically diverse children with asthma who live in high- and low-poverty neighborhoods in Austin-Travis County, TX. Our specific aims are: (1) To determine the effects of (1) moving from a high- to a low-poverty neighborhood and (2) changes in indoor and outdoor exposures on asthma phenotypes in MAP, and (2) To determine whether (1) indoor and outdoor exposures and (2) asthma phenotypes vary by neighborhood poverty in Central Texas. We will enroll 300 children with asthma sampled from high- and low-poverty neighborhoods across Austin-Travis County in the Austin-Travis County Asthma Study (ATX-AS). Establishing neighborhood differences in exposures and asthma phenotypes would support the pursuit of population-level strategies to reduce exposures, potentially resulting in long-term benefits at the population level and reductions in asthma disparities. At the individual level, should improvements in environmental exposures result in a shift to a less severe asthma phenotype, then targeting indoor and outdoor exposures could mitigate the long-term risks of fixed obstruction and chronic obstructive pulmonary disease. These proposed studies will offer outstanding training opportunities for junior clinician investigators as well as an opportunity for the PI to expand her expertise to include outdoor pollution exposure and health disparities science.